Problem: Tiffany was assigned problems 34 through 68 for homework tonight. If Tiffany did all of the problems she was assigned, how many problems did she do?
Solution: Instead of counting problems 34 through 68, we can subtract 33 from each number so we instead consider problems 1 through 35. We see that Tiffany did 35 problems. Notice that she did 35 and not 34 problems.